*HEADING
:  CONCENTRIC RINGS WITH INITIAL OVERCLOSURE [C3D8];FINITE SLIDING
*RESTART,WRITE
*NODE
*NODE
*NGEN,LINE=C,NSET=RAD_1
*NGEN,LINE=C,NSET=RAD_2
*NGEN,LINE=C,NSET=RAD_3
*NGEN,LINE=C,NSET=RAD_4
*NSET,NSET=INNODE
RAD_1,RAD_2,
*NSET,NSET=OUTNODE
RAD_3,RAD_4
*NCOPY,CHANGE NUMBER=500,OLD SET=INNODE,SHIFT,NEW SET=BACK
*NCOPY,CHANGE NUMBER=500,OLD SET=OUTNODE,SHIFT,NEW SET=BACK
*NSET,NSET=INNER,GEN
*NSET,NSET=BOUND,GEN
*ELEMENT,TYPE=C3D8
*ELGEN,ELSET=INELE
*ELGEN,ELSET=OUTELE
*ELSET,ELSET=INELE,GEN
*ELSET,ELSET=OUTELE,GEN
*SOLID SECTION, ELSET=INELE, MATERIAL=MAT_1
*SOLID SECTION, ELSET=OUTELE, MATERIAL=steel
*MATERIAL, NAME=steel
*DENSITY
8.0100E-06,
*ELASTIC, TYPE=ISO
206800.,.32
*MATERIAL, NAME=MAT_1
*DENSITY
8.0100E-06,
*ELASTIC,TYPE=ISOTROPIC
206800.,.32
*surface,NAME=IN_SURF
INELE,S4
*surface,NAME=OUT_SURF
OUTELE,S6
*CONTACT PAIR,INTERACTION=FRIC
IN_SURF,OUT_SURF
*SURFACE INTERACTION,NAME=FRIC
1.0,
*BOUNDARY
INNER,1,2
BOUND,3,3
121,2,2
621,2,2
137,2,2
637,2,2
*STEP,UNSYMM=YES
*STATIC
*EL FILE
SP,
S,
SINV,
*NODE FILE
RF,
U,
*CONTACT FILE
*CONTACT PRINT
*PRINT,CONTACT=YES
*END STEP